Exactly as GG48 says. In flower beds I mostly use a fairly heavy mulch and an edging to keep grass and weeds from creeping in from the lawn.

Be aware that Preen and similar preemergents will not discourage perennial weeds that are already established in a garden beds, things like garlic mustard or dandelion plants. What it does is that it prevents weed seeds from growing, so it discourages annual weeds and new perennial weeds.

its a PRE emergent.. better get it out there soon....

useless after they emerge ...

and dont walk thru the bed after application... else you can disturb such.. and reduce effectiveness ....

ken

ps: i have some vague recollection of using some part of a corn kernal for the same purpose.. anyone know about that???

https://www.thespruce.com/corn-gluten-herbicide-careful-timing-2152947

i think there is another term for it ....

Hum....I think I will use it. It needs to prevent cover leaves, crab grass and such. I saw one little crab grass emerging. The problem with mulch is that I can not put it on too thick at all,not enough to make a difference because it would stifle my perennials from coming up like last year and it needs to be at least three iches to do the trick.

So I will give it a shot. It is out front where I will use it. I have ponds in the back with fish and frogs and I was worried about using it in the back area where they all are last year and decided against it. Now I will just use it out front if it's ok.

Mike

Go ahead and use the Preen but then mulch once your perennials are up enough to know wher they are. The combo will work well.

mulch heavily in open spaces .... but not right up to any plant ... always leave a open ring of bare soil at the crown of a plant ... usually.. as the plant above expands... it covers the bare soil itself ....

in fall.. i used to fill the open spot.. with well mown dry leaves ... to cover the open space to avoid winter sun on bare soil ... and that stuff would be near gone by spring ...

mulch is the natural way to do this.. to suggest that you need chems of some kind.. means.. to me.. you just need to learn more about mulching ... of which we would be glad to learn you up ....

ken

ps: do understand.. that i have no aversion to properly used chems .... thats not my point in any sense ... and your question is based on a proper use ... in this case ....

How do I say this kindly? Use of any herbicide is detrimental to both soil health and our ecosystem - particularly pollinators, as anything (including "natural" or "organic" pesticides or herbicides) kill and poison insects. Mulch (with the exception of mulched leaves) is robbing your soil and the ecosystem. Your best best is to fill the space that the weeds are using with perennials that you want in your garden.

https://bethesdamagazine.com/Bethesda-Magazine/July-August-2014/Going-Natural/

It is hard to make blanket statements like the above and have them be 100% accurate :-) Or even 50% accurate for that matter. Unless the pollinators are in the soil eating the product, the Preen will have no affect on them. It only aborts seed germination....it is not transmitted into plant tissues. And many organic pest controls are very benign and target focused and will not affect pollinators either when used correctly.

And mulch does NOT rob your soil or the ecosystem! That is one of the sillier statements I've seen posted here! Mulching occurs all on its own in nature, with the accumulation of dead plant parts over time. And not just leaves.......grasses, weeds, mosses, twigs and needles all form a carpet of mulch in any natural setting if left undisturbed.

I typically don’t iuse manmade lawn and garden chemicals (other than on some invasives that are too large to remove otherwise), but I do use mulch. Any organic mulch breaks down and returns nutrients to the soil, feeds the soil herd, and improves soil texture. Chopped leaves, bark mulch, wood shavings from the planer or wood lathe, chipped arborists’ trimmings, aged manure, etc. are all good. I think if you reread the link provided she is objecting to thick layers of dyed commercial shredded woood used in place of plants, not condemning all mulches. That doesn’t make all mulches bad for the environment, and it is one gardener’s viewpoint, even if she does quote a few other folks’ opinions.

As GG48 says, lawn and garden chemicals vary greatly in their toxicity and their ability to transfer to non targets, and also their lifespan in the environment. If you choose to use them, read all labeling carefully and folllow the directions as to safety, amount, timing, etc.

I appreciate the timeliness of this post -- it reminded me that Preen is an option. It's not something I normally use (actually, I don't think I've ever used it in 20+ years of gardening), but this huge new bed I dug is a weed plantation waiting to happen. Certainly I'll mulch -- the bagged leaves are ready to go -- but freshly dug and tilled soil means thousands of weeds, even with a good layer of mulch I'll be battling them all season. Been there done that the last time we created a new planting area, lesson learned (um, battling ~2000 sq foot of weeds is NOT how I had envisioned passing beautiful summer days in the veggie patch...). So, yea - I picked up some Preen this morning. It'll be a once-and-done, though, just to get me through this freshly dug period.

I don't use pre-emergent herbicides (such as Preen), leaving them to the farmers who raise crops for a living.

I like the idea of allowing valuable perennials to self-sow, using mulch and close planting to suppress weeds, and not having to worry about even low toxicity from Preen affecting amphibians like toads.

My take is that people who gripe about weeds overtaking their perennial gardens generally are trying to do too much in an excessive space with too little time. Preen is not going to solve your weed problem any more than landscape fabric or lava rock.

Preen is intended for homeowners, not farmers. Too expensive for any acreage and farmers tend to focus on more direct approaches than any pre-emergent.

And Preen does work at suppressing weeds and quite well. Not all homeowners are heavy into perennials or even those that tend to self seed and not everyone wants a garden that is wall-to-wall plants....many prefer some definition between plants.

It is perfectly acceptable to do whatever you want maintaining your own garden but it is a bit judgemental to make assumptions about the intent of other gardeners who may benefit by taking a different tack.

I grow organic and have done so for 30+ years. Never used a synthetic chemical on my property. Never bought a bottle of RoundUp. I am a purist, for sure and I'm very happy as a grower with the way I garden and the results. I use mulch extensively to control weeds. I have used some landscape fabric under pathways. Around shrubs and trees, we use chopped leaves over cardboard or bark mulch over cardboard. We save cardboard boxes and cut them up with a box cutter in the spring and lay them down and cover with either the chopped leaves or bark mulch depending on the application. And if you don't have enough of your own cardboard boxes, if you have Freecycle in your area, someone is always posting they have free boxes to offer.

We have a lot of trees in neighboring yards, mostly Maples and one of our neighbors rakes his leaves to our lot line and pushes them over into our yard, by mutual agreement. So we have a lot of leaves. Some are Silver Maple leaves which are small and break down fast, and don't really need to be chopped. Others that are larger, we will just lay out on the lawn on a dry day and mow as usual. I love this mix of grass clippings and chopped leaves as a mulch in my vegetable beds.

In shrub beds, a layer of cardboard in the spring, covered by a couple of inches of bark mulch will last all season without weeding for the most part. We try not to replace bark mulch every year. Sometimes if we put it on thick enough we don't have to replace more than every other year. And we can feel great about recycling all that cardboard. Better still, earthworms love cardboard.

And we don't use bark mulch across the entire shrub bed. The shrub bed is along the lot line and a distance away from the areas we use the most, and some of it is under the dripline of trees, so we use chopped leaves on most of the bed and just use bark mulch along about a two foot strip along the front of the bed. That works for us, and I'm happy with it. It cuts down on the amount of bark mulch we have to use.

In my most active bed, a 20x20 combination of perennials, shrubs and annuals, I mulch over the winter with chopped leaves, remove the mulch in early spring to allow for reseeding and to get a good look at what is coming up. I keep a barrel of the leaves on hold in the garage until I've finished working in the bed. When I've moved what I want to move, sown seed where I want to sow it and then whatever bare ground is there, I will add some chopped leaves as mulch. But really there's not much bare ground left. [g] I don't use cardboard in that bed, I don't seem to need it.

As for Preen - never considered using it and because of my basic decisions to avoid synthetic chemical use, I don't end up having to think about what is in it, or what it does. I can just ignore it and garden. [g] But for your benefit here is a link that discusses the ingredients in Preen...

Ingredients in Preen

It is fabulous! Reduced our annual weeding of our DG yards by 99.9%. We used to spend hundreds of hours prodding and sifting grass carpets that sprung up as soon as the rains arrived. And if you do it as recommended, every three months, and keep extending it, you can get it down to every six monts, as it appears to be cumulative. Home Depo has the best deal on 33 lb. bags they'll deliver for free. You will love it. A great alternative to outright poisoning Mother Earth.